Hydro-pneumatic recuperator for guns



3 Sheets-Sheet l Gurney JnaEpl-L E my Iltynn A ay 29 194? J. F. JOY ET AL HYDRO-PNEUMATIC RECUPERATOR FOR GUNS Filed Sept. 12, 1941 3 Sheets-Sheet 2 J F JOY ET AL HYDRo-PNEUMATIC RECUPERATOR FOR GUNS Filed Sept. 12, 1941 l EF,

/7 d :3% uw May 20, 1947. J. F. JOY ETAL HYDRO-PNEUMATIC RECUPERATOR FOR GUNS Filed Sept. l2, V1941 3 Sheets-Sheet 3 @www Patented May 20, 1947 UNITED STATES ATENT OFFICE HYDRQ-PNEUMATIC RECUPERATOR FOR GUNS `loseph F. Joy, Claremont, N. H., and Dayton A. Gurney, Cheverly, Md.

Application September 12, 1941, Serial No. 410,614

(C1. Sil-43) 7 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes, Without the payment to usofany royalty thereon.

This invention relates to a hydro-pneumatic recuperator and more particularly to such a device. asA used in connection with a gun -recoil systern.

`In 'known mechanisms Aof this character there have been provided a recoil cylinder adapted to contain oil and a recuperator cylinder adapted t0 containoil and air under pressure, the air and oil inthe recuperator cylinder being separated by a floating piston. Infsuch mechanism oil is forced through a suitable throttling device from the recoil cylinder in-to the recuperator cylinder therebyfurther compressing the air behind the floating piston which acts to cushion the recoil movemen-t and in its reaction against the piston serves to restore the mechanism to its origina-l position. This construction is objectionable in view of the enormous amount fof Work and expense entailed in its manufacture. The recuperator cylinder and its .cooperating lioating .piston must be machined and polished to the highest :precision to withstand the :high pressure involved without per- Emitting; mixture `of the gas and oil. The -high packing pressures Anecessitated in Vmaintaining such aseparation give rise to a high degree of static frictionbetween the `piston packing and cylinder Walls. 'Since static friction is Amuch greaterxthanmovingfriction it follows thai; the gun supporting structure must. absorb the heavy shock required to Aovercome static friction before yield can occur. Furthermore, by reason-oftheir precision manufacture, replacement or repairs inl-the iield are not practical and such work can only bemproperlyxdone at the factory or at an arsenal especially yequipped for such Work.

Attemptshave been made to maintain oil and gas-.yseparationnand Veliminate the floating piston in such :mechanisms by the provision of a separate collapsible .air -crm-tai-ner or ibelloyvs placed Withinztherecupelator cylinder.

rSuch attempts, however, have not vproven to bepractical, one Aof the reasons for `their failure being that -,proyisions .have not-been made to preventxtheflllpure ofthe flexible container or sealing-means` therefor in theeventlof `the leakage of a considerable quantity of oil.

-Inview ofthe foregoing `*it :is an object of this invention feo-provide :for fa vpractically frictionless separation of the oil andlgasin a construction-.ofsimplefform ...which is capable offless costly manufacture andgismore convenient-to .'use.

Another object is that of providing forquick and convenient repair `and replacement'in the eld or at other pontsremote from the factory ory arsenals.

It is a further object to provide means for the protection of the mechanism in the event foil leakage to an extent sufficient to unbalance the pressures in the mechanism.

While, obviously, the unit herein described is suitable for use in any hydro-pneumatic system in which it is desired to maintain a. separation between gas and fluidthe description appended will refer particularly toits application in a-recoilbrake for guns.

The specific natu-re ofthe invention as Well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

Figure 1 is a longitudinal cross section of a portion of a gun recoil mechanism embody-ing our invention.

Figure 2 is .an enlarged longitudinal crosssection .of a portion ofthe mechanism shown-in Fig, 1.

Figure 3 a vertical section ltakenon Athe line 3 3 of Fig. 2. l

Figure 4 is a view similar to Figure 21showing a modied form of our invention.

Figure 5 is a similar view of another modification.

Figure 6 is a vertical sectiontaken on 6.-6' of Fig. 5.

Figure 7 is a :View similar to Fig. 2 showing another modification.

Figure 8 is a vertical section taken on the line -Bof Fig. 7.

Referring to the drawings-by characters ofreference, therewis shown in Fig. 1 a breech lug' I0 of a vgun mounted for recoil in the normal manner,` the breech lug being secured to -the piston rod I I of the recoil'mechanism in any convenient manner. Broadly the recoil system shown comprises aconventional recoil cylinder I-2 connected through suitable throttling valves I3 and 'M with a recuperator cylinder 15. VUpon recoil'of the gun oil Vis forced from the recoil cylinder in the usual manner into the recuperator cylinder. In our invention separation between'the oil and air or other lgas'in the recuperator .cylinder is maintained by a substantially `frictionless fdithe line aphragmror flexible member .-IB of synthetic rubber orother-exible oil resisting material. :In the recoil system, shown an. accumulator `cylinder-LTI is connected ,tothe recuperator toallow fom-n.-

creased gas volume and added length of recoil, but it must be understood that the usefulness of the invention is not limited to use with a separate accumulator as such means can beas well cal ends of the thimbles I8 and I9 are internally threaded for securement to the threaded ends of an inner steel tube or supporting sleeve 24. Engaging shouldered extensions 25 and 2S on the gland members is another supporting sleeve in the form of an outer steel tube 27. Both of the supporting sleeves are perforated or drilled with a multiplicity of small holes which permit the free passage of oil or gas but are of such a small size as to effectively limit the movement of the flexible member in the event of an unbalanced pressure condition tending to abnormally expand or contract the flexible member. It will benoted that the conical form of the thimbles and of the interior of the extension on 4the gland members prevents any local concentration of strain which would occur if the chamber were forced to accommodate itself to abrupt variations in the cross section of the supporting structure. The thimble I8 is provided with a hollow, threaded male extension 28 for securing the exible member in the cylinder I5 by engagement with the oil inlet head 29. Communication with the accumulator II is provided through suitable tubing 30 connected with the gas inlet head 3 I.

The procedure in placing the recoil mechanism in service after mounting consists in filling the accumulator cylinder and that part of the recuperator cylinder exterior to the flexible member with gas to a predetermined Working pressure. In so doing the flexible member will be forced into contact with the outer wall of the inner supporting sleeve 24. As a second step the recoil cylinder and the interior of the flexible member are charged with oil or other fluid forming the hydraulic medium. Care should be exercised during the introduction of fluid to eliminate air bubbles or voids within the system as such may result in the aeration or emulsification of the fluid, a condition conducive to erratic and generally unsatisfactory performance at the throttling orifices. When the system has been completely lled and purged of all imprisoned air bubbles it should be closed to the atmosphere and a sufficient supply of reserve fluid added to force the exible tube away from the outer Surface `of the inner supporting sleeve 24 to what might be called a working distance.

The recoil resulting from gun ring causes a displacement of fluid in the recoil cylinder as the recoil piston forces the contained oil under high pressures and velocities through the throttling orifice into the interior of the expansion chamber unit in the recuperator cylinder. In so doing the fluid pressure resulting from the recoil reacts through the apertures in the tube 24 upon, the inner surface of the flexible member I6 causing the latter to expand against the external gas pressure. Since the separation afforded by the flexible member is practically frictionless there will be no severe peak shock to the gun supporting mechanism on firing as is the case with a so-called floating piston and the increase in fluid pressure will be reflected almost simultaneously by an increase in gas pressure. Fluid flow from the recoil cylinder to the recuperator will continue until the recoil energy of the gun has been absorbed by the combined action of fluid throttling and the above mentioned increased gas pressure in the recuperator system. Upon conclusion of the recoil the energy absorbed therefrom is available for returning the gun to its normal ring position. During this counterrecoil the pressure exerted by the compressed gas acts to substantially reverse the operations described above, the reversed flow of uid taking place through the one way valve I4 to act upon the piston in the recoil cylinder.

Figure 4 discloses a modification in the method of applying the invention to the recuperator cylinder. In this case the threaded male extension 28(a) is connected to the gas inlet head 3Ia. The structures are substantially identical and the operation is the same except that in the modified form gas is used inside the expansion chamber with oil surrounding the chamber. The chamber therefore contracts on recoil and expands on counterrecoil, the reverse of the operation hereinbefore described. The reference numerals applied to Fig. 4 are ythe same as those used in Fig. 2 with the addition of the subscript (a).

It has been found from experiments that the more elastic materials, possessing relatively high strain limits, are as a general thing more permeable than materials possessing less elasticity. High permeability permits gas absorption by the oil through the walls of the separating material, particularly under conditions of high pressure. Under the latter conditions it may be `desirable to sacrifice the quality of elasticity for a decrease in permeability. The construction shown in Figures 5 to 8 provides for the use of such material.

In the modification of the invention shown in Figures 5 and 6 an expansion chamber of material having relatively low strain limits but corisiderable flexibility is secured in the mechanism in a manner similar to that used with the above described constructions. In this case, however, the flexible chamber I6(b) is formed with a section intermediate its ends of enlarged diameter. The chamber is installed under sufficient longitudinal tension to cause the large diametered section to assume a fluted outline as shown in the cross section, Fig. 6. In this case as in Fig. 4, gas is used inside the bag and fluid on the outside. Obviously as the gas is initially charged into the bag-like chamber I6(b) the Walls thereof will be caused to conform to the contour of the outer steel retaining tube 21(1)). It is also clear that as oil is forced from the recoil cylinder into the recuperator I5(b) the chamber will be caused to collapse about the inner steel tube 24h. By means of this construction the expansion chamber is required to stretch only that limited amount necessary for flexibility and hence may be formed of a more nearly impermeable material. Figure 5 also shows a modified means of securing the expansion chamber unit within the recuperator cylinder. The thimble I8(b) is in this case provided with a packing ring 32 and a clamping ring 33 forced into engagement with the packing ring by bolts 34 whereby the packing ring is expanded into sealing engagement with the walls of the recuperator cylinder I5(b). In view of the foregoing descriptions of the operation of the other Of, the Iiieiilberi 3l and externellr 'threadeiif4 te,

essere annuler member 33 slidebly engaging the recuperator cylinder l(c).' threadably `engagingY the member 39 act upon a Clamping. ring 4l placingthe packing ring 42 under compression and engaging the ferrule 3S to secure the assembly against longitudinal movementy and to securely seal the tube member 35 to the wall of the recuperator |50. The collapsed wall portion of the inner steel member 31 is perforated ordrilled witliaVA plur'al'ity'of .holes 43 of suiilcient size and number to freely pass uid rhesiierine s sesiiive slippen i0 the flesiiie' TQ risse 'iiieiiiiiiiii servieethe ees pressure illihe'eeiilnlileiei: esiiieeiiiiereier is builtunte a'iiedeiiiiii'riefi level: Q bvieusiy the flexible beg will 'be sllsiseisleeiitihe collapsed tube membei# and uren iiiiidbeiile fereed inte the reeiliiereier fiemihe. reeeilevliiifler will be esegesi us is iis Qrisiiielsiiapesinee the expansion ef ilie. eheiilberiiiiliie Cese seisists lereeiyiri the fillingI of a collapsedbag member it will be apparent that the stretching of the bag member may beheld to very low limits.

Obviously an expansion chamber of thetype herein describedhas al wide application in hydropneumatic devices of all kinds. It must, therefore, be understoodthat in describing the inventOIl as appliedtd a. gun recoil` mechanism no limitations upon the invention are intended other than those imposed by the appended claims.

We claim:

1. In a hydro-pneumatic device, a cylinder containing a first fluid, an apertured member in said cylinder in communication with a supply of second fluid, flexible, tubular separating means on said member in fluid-tight engagement therewith, and supporting means exterior to said separating means extending substantially coextensive therewith and engaging said member whereby the expansion of said separating means by the second fluid is limited, said supporting means being provided with apertures whereby the rst fluid may have access to the exterior of said separating means, said apertures being of insufficient size to allow the separating means to be displaced therethrough by pressure of the second fluid in the interior of said separating means.

2. In an artillery weapon a hydro-pneumatic recoil mechanism for absorbing the recoil forces of firing said weapon comprising means operatively connected to said weapon and adapted to produce pressure in a liquid medium associated therewith, means dening a source of gas under pressure operative to oppose the force within said pressure liquid, a recuperator cylinder containing at least a part of said pressure liquid and said pressure gas, an elongated generally cylindrical elastic diaphragm Within said recuperator cylinder separating said gas from said liquid therein, and a pair of axially spaced clamping devices lying within said recuperator cylinder and opercollapsediafeim s ereseeiiteid Crees set screws Ml AGI 4 therewith, m

absorbing the reeeilfierees weites r1y semer-ismamearisesereeri tessili; weapon. and adapted t0 ein e liqiiidiilefiiiira associated s. .deiliiiiies iiree ef gesunder ve te oepeseihe folies-within said e -ligiiiili e ,fresueeiaier -erli @le sentaisleesieisaiifoiesaidl-pr .i111 saidi site fegesi elongated` generally-.erlieffiselsla,isdiepbissmwithiii saisi resinas Cylinder serai, sie; seid1 ses. freie said smid xieily spaeedfelaeieing their cernes?? @99:1106- Ppsiteeiids @issiedie- Phi einst lila-seiidferllmienf saidelanisiiie de.-

ieseieiiises secures, in en en d for said refaireraserY ermee im@ ressiiregasiiite -diarliiaerabut egeludins Seide. mesherlism.- being e911- stru'cted and arranged whereby ubstantially, no iriiiial-iilesliai1iasl-filetieii Oppesmefresoll Inoveiiieiiie se, Wears-ii is. nresluseelbrfseldriiieeber iiisir1 .eeii fir-iris said; wespen 4f Iiiv arl ai" Pera Weapon ahaha-pneumatic riesen-meen @f1-hiring sai ism for absorbing thereeoil forces tivelysorlrleeied tnsaidveanon and adapted t0 produapressure in a liquidimedium, associated therewith, means defining a source of gas under pressure operative to oppose the force within said pressure liquid, a recuperator cylinder containing at least a part of said pressure liquid and said pressure gas, an elongated generally cylindrical elastic diaphragm within said recuperator cylinder separating said gas from said liquid therein, and a pair of axially spaced clamping devices lying within said recuperator cylinder and operative to secure opposite ends of said diaphragm within said cylinder, said clamping devices each including a pair of inwardly and outwardly tapering faces adjacent their connection with said diaphragm, at least one of said clamping devices being apertured and including a gland structure operative to seal the interior of said diaphragm against the admission of liquid from said cylinder while permitting free access of said pressure gas thereto, said mechanism being construc-ted and arranged whereby substantially no initial mechanical friction opposing recoil movement of said weapon is produced by said mechanism upon firing said weapon.

5. In an artillery weapon a hydro-pneumatic recoil mechanism for absorbing the recoil forces of ring said weapon comprising means operatively connected to said weapon and adapted to produce pressure in a liquid medium associated therewith, means defining a source of gas under pressure operative to oppose the force Within said pressure liquid, a recuperator cylinder containing at least a part of said pressure liquid and said pressure gas, an elongated generally cylin- @superster esslingen iig ener-iure therein an being- Wespen Comprising means- Opeladrical elastic diaphragm within said recuperator cylinder separating said gas from said liquid therein, said diaphragm being formed with longitudinally running corrugations in at least part of its length, and a pair of axially spaced clamping devices lying within said recuperator cylinder and operative to secure opposite ends of said diaphragm within said cylinder, said clamping devices each including a pair of inwardly and outwardly tapering faces adjacent their connection with said diaphragm, said mechanism being constructed and arranged whereby substantially no initial mechanical friction opposing recoil movement of said weapon is produced by said mechanism upon firing said weapon.

6. In an artillery weapon a hydro-pneumatic recoil mechanism for absorbing the recoil forces of firing said weapon comprising means operatively connected to said weapon and adapted to produce pressure in a liquid medium associated therewith, means defining a source of gas under pressure operative to oppose the force within said pressure liquid, a recuperator cylinder containing at least a part of said pressure liquid and said pressure gas, an elongated generally cylindrical elastic diaphragm within said recuperator cylinder separating said gas from said liquid therein, said diaphragm being formed with longitudinally running corrugations in at least part of its length, said mechanism being constructed and arranged whereby substantially no initial mechanical friction opposing recoil movement of said weapon is produced by said mechanism upon ring said weapon.

7. In a hydro-pneumatic device, a cylinder in communication with a source of liquid pressure, a member having an opening therethrough secured in an end of said cylinder, said opening being in communication with a source of gas pressure, flexible tubular separating means hav- 4 ing one end secured to said member in gas tight engagement therewith, closure means for the other end of said separating means, said tubular separating means being formed with a portion intermediate its ends of enlarged diameter, means securing said separating means between said member and said closure means under 1ongitudinal tension sufficient to cause the section of enlarged diameter to assume a longitudinally iuted form, and apertured tubular supporting means exterior to said separating means and engaging said member and said closure means whereby the expansion of said separating means is limited, said apertures being of insuicient size to allow the separating means to be displaced therethrough by gas pressure inside said separating means.

JOSEPH 1i'. JOY.

DAYTON A. GURNEY.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,729,565 Caretta Sept. 24, 1929 1,956,668 Charles May 1, 1934 1,622,892 Wadsworth Mar. 29, 1927 1,436,144 Bernat Nov. 2l, 1922 2,278,688 Caminez Apr. 7, 1942 2,290,337 Knauth July 21, 1942 2,319,460 Johnston May 18, 1943 2,105,160 Piquerez Jan. 11, 1938 2,260,850 Brazier et al. Oct. 28, 1941 713,691 Schneider et al Nov. 18, 1902 FOREIGN PATENTS Number Country Date 754,307 France Aug. 28, 1933 253,033 Italy May 2, 1927 17,403 Great Britain Aug. 6, 1896 478,591 Great Britain Jan. 20, 1938 319,617 France July 26, 1902 

